MCC5500 call director failure?

[dag]

We have a MCC5500 console with 4 positions. Recently one position stopped switching Select audio to the Select speaker when an off hook indication comes in on the Call Director port. The Select audio remained in the headset along with the call director audio. A spare CAB was put in place, fixing the problem. A week later we receive a call about the same position with the same problem. The telephone system is a Solacom system, none of the other positions exhibit this behavior.

The center has upgraded their computers to Windows 10 machines recently and all the settings are correct.